Field of the Invention
The present invention relates to an infrared ray cutting film, infrared ray cutting laminated glass, and an infrared ray cutting member.
Background Art
In recent years, as one of the energy saving measures for reducing carbon dioxide, heat ray shieldability-imparting materials have been developed for windows of vehicles and buildings. From the viewpoint of heat ray shieldability (heat shielding performance), heat ray reflection types with no reradiation are desired instead of heat ray absorbing types with indoor reradiation of absorbed light (in an amount of approximately ⅓ of the absorbed solar energy), for which various proposals have been made. Further, in addition to heat ray shieldability, high visible light transmittance (invisibility) is demanded for the heat ray shieldability-imparting materials for windows of vehicles and buildings from a viewpoint of safety or the like and robustness (light resistance) is also demanded since the materials are used for a long period of time.
Meanwhile, a technique (for example, see Patent Reference 1) of reflecting infrared rays using a cholesteric liquid crystal is known. Patent Reference 1 discloses that a heat ray shielding material with high heat shielding performance can be provided from a heat ray shielding material which has a cholesteric liquid crystal layer and in which a selective reflection wavelength of the cholesteric liquid crystal layer is in an infrared light region.
Further, an infrared ray cutting technology combining reflection using a cholesteric liquid crystal and absorption of infrared rays using metal fine particles is known. For example, Patent Reference 2 discloses that a near infrared ray absorbing material obtained by laminating a near infrared ray absorbing layer and a cholesteric liquid crystal layer on a base, in which the near infrared ray absorbing layer contains a resin and an inorganic near infrared ray absorbent having an average particle size of 40 nm to 200 nm; the cholesteric liquid crystal layer contains a cholesteric liquid crystal material which has a fixed cholesteric structure and whose selective reflection wavelength is in a red light region; and the color of reflection does not exhibit a blue color and near infrared rays are effectively absorbed by the infrared ray absorbing material having visible light transmittance; and which has high visible light transmittance and excellent transparency can be provided. However, in regard to absorption or reflection by the metal fine particles described in Patent Reference 2, it cannot be said that absorption or reflection in a wavelength region of 750 nm to 920 nm, which has a high level of energy among sunlight, is sufficient.
Patent References 1 and 2 do not contain a description of use of near infrared ray absorbing pigments, but an example of forming a near infrared ray absorbing layer using a near infrared ray absorbing pigment is known. For example, in Patent References 3 and 4, an example of using a pyrrolopyrrole pigment as a near infrared ray absorbing compound is known. However, a combination of a near infrared ray absorbing layer and a near infrared ray reflection layer is not even disclosed or suggested in Patent References 3 and 4.
Patent Reference 5 discloses an example of combining a near infrared ray absorbing layer using two or more kinds of organic pigments that absorb near infrared rays at approximately 800 nm and an infrared ray reflection layer using a cholesteric liquid crystal and describes that the pigment mixing amount can be reduced by making an infrared ray cutting filter for a PDP have such a configuration.